I was recently selected as an "Adobe Influencer" and have been playing with CS4. There are a lot of amazing changes in the updated version and below is one of my favorites:Check out the "Content Aware Scale" Tool. Here is an image of my cousin with its original aspect ratio:
I am usually a full frame shooter and have significant content from edge to edge. I always hate having to crop a photo to fit standard frames (ex - 8 x 10 crop when a full frame image is 8 x 12 - bye, bye 2 inches of my image!). The brilliant technicians at Adobe came up with a tool that will intelligently crop your images analyzing which data can afford to be lost without effecting or stretching the important aspects of the image.
It took me about 1 minute to scale the image below to a frame proportioned 8 x 10. I just duplicated layer, went file - content aware square and made the crop. Powerful stuff!